The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Fully flexible valve actuation (FFVA) systems also referred to as camless systems, include electro-magnetic (electro-mechanical), electro-hydraulic and electro-pneumatic systems. Known electro-magnetic systems are able to generate controllable valve opening timing and duration. These devices, however, generally have high valve-seating velocities. They are also limited by having fixed valve lift operation. Known electro-hydraulic systems provide fully controllable valve-lift events. For these systems, digital and/or proportional valves have been implemented to control hydraulic fluid flow to open and close the engine valve. Potential issues with the electro-hydraulic mechanisms may include system controllability and energy consumption. Known electro-pneumatic systems employ pneumatic actuators to open and close the engine valve. Potential issues with the electro-pneumatic system include low power density and leakage.